MEXICAN DEVIL
Ageratina adenophora
Download the PDF
DESCRIPTION
Mexican devil is a perennial. It’s bushy, and forms dense colonies up to 2-3 metres tall that smother native species and prevent their regeneration. It’s a fast growing plant and produces a great many viable seeds, so left uncontrolled this plant can spread rapidly. It originates, as the common name implies, from Mexico.
The flowers are small (5mm or so), creamy-white and appear in dense clusters. It flowers Aug – Dec.
Following flowering, many small black five-angled seeds appear.
The leaves are arranged in opposite pairs and are dark green on top, lighter green underneath. They’re diamond shaped, up to about 8mm long, with irregular, round-toothed edges.
Branches are also arranged in opposite pairs, and the leaf stems are woody, hairy and very often tinged with purple. Many plants have visible galls (growths) on the stems caused by a parasitic fly. The stems can die back over winter.
Roots are fibrous.
There’s a very similar plant called mist flower (Ageratina riparia) that has narrower leaves and slightly smaller though similar flowers. Mist flower can be treated and controlled similarly to Mexican devil.
-web.jpg)
HABITAT
Prefers riparian areas, especially where damp, forest margins and waste areas. It handles drought as well as damp, and can tolerate moderate shade.
Mexican devil is common in the upper half of the North Island. It’s subject to Pest Plant Management Strategies (check with your regional authority for details).
POISONOUS
This plant is toxic to livestock, and there have been confirmed incidents involving horses in particular, in both NZ and Australia.
PHYSICAL CONTROL
Individual and isolated plants can be hand pulled, ensuring the full root system is taken, and all material removed from the site and buried or burnt
HERBICIDES TO CONTROL MEXICAN DEVIL
Mexican devil can be successfully controlled with herbicides anytime that it’s growing actively, so from early spring right through to late autumn depending on local conditions.
Weed Wiping Herbicides to Kill Mexican Devil
- 2g MSF600 per litre of water.
- G-360 GLYPHOSATE – 330ml/L water, or G-540 GLYPHOSATE – 220ml/L water, or Granny Herbicide – 150g per litre of water.
Cut and Swab or Paste Herbicides to Kill Mexican Devil
- Cut stems close to the ground and swab the fresh cut stump with 5g MSF600 per litre of water.
- Cut'n'Paste MetGel. Apply a 2-4mm thick layer of gel on the freshly cut stump.
Hand Spray Weedkillers to Kill Mexican Devil
- 200ml G-360 GLYPHOSATE, or 133ml G-540 GLYPHOSATE, or 90g Granny Herbicide – 10L water. Add SuperWetter penetrant at 10ml per 10 litres.
- 5g MSF600 per 10 litres of water. Add SuperWetter penetrant at 10ml per 10 litres.
-web.jpg)